Microbio Pre-lab 5 Quiz

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Microbio Pre-lab 5 Quiz
2013-10-22 22:36:40

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  1. What is the component in acid-fast organisms that makes the stain possible ?
    Mycolic Acid
  2. Is Mycolic acid a waxy substance ?
  3. What is the difference between the Ziehl-Neelsen method (ZN) and the Kinyoun method (K) ?
    The ZN method used heat in the staining process and the K method is cold
  4. Why is the sheep serum used instead of water ?
    The acid-fast organisms is slippery , so it adheres to the sheep serum.
  5. When acid-fast organisms repels most stains what are they seen as ?
    Weakly gram positive
  6. Why is carbolfuchsin used as the primary stain ?
    It is a phenolic compound that penetrates the waxy cell wall
  7. Why is heat applied in the Ziehl-Neelsen method ?
    It allows melts the waxy layer and allows the stain to move into the cell.
  8. What is the decolorizer for ?
    It is for non acid-fast organisms. The acid-fast organisms can resist the decolorization
  9. What color are Acid fast organisms ?
    Reddish –purple
  10. What color will non-acid fast organisms be ?
    The color of the secondary stain used .
  11. How does the Kinyoun method work ?
    It uses a stronger carbolfuchsin stain that penetrates the waxy cell , but it is not as effective as the heat.
  12. What genus is the acid-fast used for ?
    Actinomycete organisms and

    Oocysts of coccidian parasites
  13. What morphology is Acid Fast typically used for  ?
    Acid -Fast Bacilli (AFB) - has a 90 % predictive value.